It doesn't look like we are going to get a definitive result tonight – to put it mildly – so I'm going to call it a day there. Here is where things stand, courtesy of John Hooper and Lizzy Davies in Rome:

Italy on Monday night risked pitching into political turmoil as projections of the result of its general election pointed to a hung parliament and confirmed that the anti-establishment Five Star Movement (M5S), led by an ex-comedian, Beppe Grillo, had exploded onto the national stage.

Projections suggested on balance that the centre-left would take the lower house, the Chamber of Deputies, by a tiny margin. But they also indicated that a resurgent right led by Silvio Berlusconi would have slightly more seats - though not necessarily more votes - in the Senate.

Crucially, it seemed certain that neither right nor left could obtain an outright majority in the upper house, where the balance would be held by the M5S. So far, Grillo has ruled out supporting either side in his drive to sweep away Italy’s existing political parties and the cronyistic culture they support.

Exceeding even the most adventurous pre-electoral predictions, the populist M5S was set to emerge as Italy’s biggest single party - a result that will send shock waves through the eurozone and beyond. Because it is running alone and not in a coalition, however, Grillo’s movement lagged the two big alliances in the number of seats.

The emerging result indicated that fresh elections were a strong possibility and, at best, foreshadowed a weak government unable to pass the tough reforms Italy needs to enhance its grim economic prospects.

European leaders have been desperate to see a stable government in Italy, and are likely to be horrified and aghast at the triumph of populism in the eurozone’s third biggest economy. The likely results threatens to reignite the question of the euro’s stability following months of relative calm.

Election laws in Italy mean the biggest party in the Chamber of Deputies is guaranteed a 54% majority. But the Senate has no such "majority bonus". The latest projection from Rai shows Berlusconi's bloc winning 112 Senate seats, the centre-left 105, Grillo 64, with Monti's centrists on only 20. The Senate majority is 158.

8.56pm GMT

John Hooper sends this from Nicholas Spiro of Spiro Sovereign Strategy:

Based on current projections, financial markets are facing the worst of both worlds in Italy: a full-blown political crisis in the eurozone's third-largest economy and a severe setback for the liberal economic agenda championed by Mr Monti. At this stage, even the formation of a government is likely to prove a major challenge.

8.49pm GMT

La Stampa is quoting Beppe Grillo as saying: "I am tired. In three years we have become the No 1 party in Italy. Nobody can beat us. The government? The only solution is a PD-PDL alliance" – an alliance between Bersani's leftwing Democratic party and Berlusconi's rightwing People of Freedom.

8.17pm GMT

Mattia Garofalo, 31, a literary agent from Turin who voted for Bersani's Democratic party, told my colleague Lizzy Davies he was disappointed even though the situation was "incredibly foreseeable".

"Italy always needs to touch the worst possible point before it gets back up," he said. "I pretty much think there'll be elections in a year, once again." The strong showing of the Five Star Movement did not scare him, he added.

"How can things get worse? We have an ex-prime minister who's been found guilty for tax fraud and who's on trial for sleeping with an underage prostitute. We have a centre-left party which although it says it didn't have any responsibility in the Monte dei Paschi [banking scandal] it obviously did. And just the fact that there is a drastic need for change in the people who are there [in parliament]; even if half the new people won't be better, at least it's not the same people doing the same things. That's why I'm not scared."

8.15pm GMT

Summary

As the results of the Italian election continue to be counted, here is a summary of where things stand so far:

•Current projections suggest that against all predictions Silvio Berlusconi’s rightwing coalition will dominate the Italian Senate – but Pier Luigi Bersani’s leftwing grouping will end up the biggest in the Chamber of Deputies. The result for Italy seems likely to be gridlock – and perhaps further elections within months. It is thought impossible that Berlusconi and Bersani might team up in a grand coalition.

•Satirist Beppe Grillo has established his Five Star Movement as a political force to be reckoned with as his anti-establishment insurgents seem likely to end up the biggest single party in a political system usually made up of small parties working in coalition. Who the so-called Grillini will side with and who they will oppose is an open question.

•The markets seemed pleased earlier on when exit polls seemed to show Bersani on course for victory – but plummeted when news broke of Berlusconi’s likely victory in the Senate. The euro has fallen to a six-week low against the dollar. The Dow Jones fell 87.44 points. The interest paid on Italian 10-year bonds rose to 4.55% – although the Milan stock exchange did close 0.7% up. A Bersani-led coalition, perhaps one including current centrist PM Mario Monti, had been expected to keep up the EU’s austerity programme. Italy’s economic turmoil prompted the worst period of the eurozone crisis in 2011.

•The turnout of just under 75% was the lowest in national elections since the republic was formed after the second world war, with disgust with politicians as well as the bad weather cited as a cause.

Updated at 8.22pm GMT

7.36pm GMT

Beppe Grillo talks with the press as he arrives at a polling station in Genoa. Photograph: Riccardo Arata/EPA

Twice in the last two decades, outsiders have burst onto the political scene. Both have done so by exploiting their understanding of the medium that was most relevant at the time. Berlusconi took Italy by storm in 1994 after creating a virtual monopoly of private television; Grillo has relied instead on making himself a master of digital communication.

7.18pm GMT

The deadlock in Italy is threatening to inflame the global financial crisis, Graeme Wearden reports.

The euro has just fallen to a six-week low against the US dollar, dropping below the $1.31 mark. And on Wall Street, the Dow Jones industrial average has fallen up to 100 points in afternoon trading, or around 0.7%.

- neither the centre-left nor the centre-right will have a majority in the senate, both even with Monti’s support wouldn’t reach the required 158 seats.

- in the lower house, projections have the centre-left just ahead (and would therefore win 55% of seats). M5S will be the largest party ...

We need to wait for final results to see who has a majority in the lower house, but that aside, there won’t be a majority in the senate needed to form a government. Italy will need to return to the polls in the near future.

A few challenges though for the new parliament:

1) it will need to elect presidents for both chambers

2) will need to support an interim/caretaker government

3) will need to elect a new president (who can then call an election) with a 2/3 (of parliament, lower house + senate, as a whole) majority - current President, Napolitano, may resign early to expedite this

4) will need to change the voting law

5) and will need to guarantee a minimum of stability in this interim period.

How the above will happen via ad hoc alliances and without a clear majority in the Senate, and the implications of all this, is anyone’s guess.

7.09pm GMT

Here is Rai's most recent projection for the Senate:

Senate:

Centre-right coalition (Berlusconi): 30.5%

Centre-left coalition (Bersani): 31.1%

Five Star Movement (Grillo): 24.4%

Centrist coalition (Monti): 9.5%

7.00pm GMT

While the implications of the elections results are mired in uncertainty, one thing is abundantly clear, writes Lizzy Davies in Rome: this was not good news for Mario Monti.

The outgoing technocrat prime minister, once dubbed "Super Mario" for his prowess at the European commission, was super no longer. His centrist alliance seemed all but certain to come a poor fourth - to a comedian.

“What a disaster for Monti. A huge communications failure,” was the verdict of Bill Emmott, the journalist whose damning documentary about Italy, Girlfriend in a Coma, has been touring Italy in recent weeks.

The Twitter account of his film succinctly remarked: “Monti in a Coma. What a waste.”

A day before, Emmott, a former editor of the Economist, had tweeted that the 69-year-old was the “only choice” for the country. Italians, it seemed, did not agree.

Battered by 13 months of the technocrat government’s austerity measures, many voters had grown to loathe Monti for - as they saw it - turning the screw on them with tax hikes when they were already struggling in a recession. Others going to the polls said they recognised he had done a necessary and unenviable job of saving the country from financial disaster - but that it was now time for someone new.

Since Monti delighted the markets in December by announcing his intention to enter politics, he has undergone an unlikely image transformation from mild-mannered professor to sharp-tongued electoral candidate. He has lashed out at his rivals, deriding Silvio Berlusconi as a “pied piper” leading Italy to doom and exhorting Democratic Party leader Pier Luigi Bersani to dump his left-wing allies. He even, on one occasion, suffered the indignity of cuddling a puppy for the camera.

But with the memory of his reform agenda still fresh in their memory, Italian voters do not appear to have wanted more of the same. James Walston of the American University of Rome said the poor showing was partly down to the fact that, in abandoning his neutrality and entering the political sphere, Monti had lost his key strength. But it was also, he said, simply that alongside Beppe Grillo and Berlusconi, the dry, understated economist had found it difficult to shine in the campaign.

“He messed up as a performer,” said Walston. “He was surpassed by two master performers, and even by Bersani.”

Mario Monti in front of a photograph of Silvio Berlusconi. Photograph: Alessandro Bianchi/Reuters

Updated at 7.19pm GMT

6.56pm GMT

With a third of the votes counted, the Ministry of Interior's figures for the Chamber of Deputies are also showing the leftwing coalition in the lead:

With the projections for the Senate showing a lead for Berluconi’s rightwing coalition and the projections for the Chamber of Deputies showing a very slight lead for Bersani’s leftwing coalition, he said:

This is very unpredictable. As the results come in we seem to have a split majority in the two houses, the Chamber and the Senate, and one should also remember that in Italy, unlike most countries but very similar to the US, both chambers have equal powers, and they have in particular the power to vote a new cabinet in. So a split majority would be extremely problematic …

Caramani said the main winner of the elections so far was Beppe Grillo, and his Five Star Movement, “which will make the situation even more unpredictable, since we have no indication how they will ally, if they will ally, with the two major parties”.

Grillo has said he will not go into coalition with the major parties, but he himself is not a candidate. Might his party candidates chose to go into coalition after all?

This is, I think, impossible for anyone to say. The situation is very similar to 1994 when the Lega Nord, the Northern League, for the first time came into the national parliament and many people had no idea how they would behave.

“Italy does not have a tradition of minority government,” Caramani said, but it was the possibility that the Grillini – as Grillo’s party members are called – could end up supporting a government on a vote-by-vote basis.

Caramani said he thought a new election in a few months’ time was unlikely. He said he thought Italian president Giorgio Napolitano would “push very strongly” for parliamentarians of one stripe or another.

I don’t think at all that this current president is inclined to new elections; that would send a very, very negative signal to the international community, to the markets, to their European partners. But this current president is to be replaced in the coming two months and we don’t know at all who the new president will be and what his or her inclinations concerning a new election will be.

6.20pm GMT

If correct, those figures suggest we are headed for gridlock, with Berlusconi's centre-right coalition dominating the Senate and Bersani's leftwing coalition leading in the Chamber of Deputies. But the figures for both coalitions are so close it's possible the right could take the lead in both chambers.

6.19pm GMT

La Stampa reports that Rai has given its first projection for the Chamber of Deputies, and it shows the leftwing coalition just marginally ahead. Here are the figures:

The early optimism when the first exit polls came out, suggesting a centre-left win, evaporated once later projections pointed to a lead for Berlusconi's centre-right coalition.

Italian government bonds also fell in value in late trading, and 10-year bonds were changing hands at an effective interest rate of 4.55%. They too swung in value thorough the afternoon, falling from 4.466% at 10am to 4.182% at 2:38pm, and then swinging back up again (see chart below).

Italy's borrowing costs are a crucial factor in the eurozone debt crisis. The country has a total national debt of around €2 trillion, and must issue more than €400bn of new bonds this year to cover debts that mature and must be repaid.

Italian bond yields recovered under Mario Monti's leadership, particularly after the European Central Bank offered to support any country which signs up to a stringent programme of reforms. That programme has not been activated yet.

Italian 10-year bond yield data today. Graphic: Tradeweb

Updated at 8.07pm GMT

5.30pm GMT

British thinktank Demos has been studying the Beppe Grillo phenomenon. The thinktank has surveyed Facebook supporters of the Five Star Movement and found that only 8% trust the government, 3% trust political parties, 2% trust parliament, 2% trust banks and financial institutions and 6% trust big companies – lower, on every measure, than the Italian general public. Only 11% trust the press (against 34% of Italians overall) and less than 4% trust TV (against 40% of Italians). In stark contrast to this, 76% of Grillo's Facebook fans trust the internet, where the movement was born and which it has used to organise itself. Demos writes:

Other findings of the research include:

Those surveyed are more likely to be male and to be older.

They are more likely to be well-qualified, with 54% reporting they had a high school diploma (compared to the Italian average of 41%), but are also more likely to be unemployed – 19% compared to the Italian average of 7.9%.

On average, they self-identify as left-wing: when asked to place themselves on a spectrum ranging from 1-10, with 1 being furthest left and 10 furthest right, the average score for respondents was 3.88.

When asked to name their top two concerns, supporters chose the economic situation (62%) and unemployment (61%). A distant third was taxation at 41%.

They are broadly positive about immigration: more likely than the Italian public in general to view immigration as an opportunity (56% versus 28%).

Jamie Bartlett, the author of the report, said:

Beppe Grillo and his movement have come from nowhere to second place in the polls in the space of three years. The combination of his charismatic anti-establishment rhetoric, and the power of new social media to reach out to audiences beyond the confines of more traditional media has proved a lethal cocktail, and leaves him a force to be reckoned with in the run-up to this year’s election.

The political sea-change heralded by the rise of online organising is not limited to Italy, however. At Demos we have been researching the growth of online political movements for the past two years. Many of the concerns of Grillo’s supporters are shared by people across Europe and are reflected in declining trust in political institutions, falling political party membership and ever-lower voter turnout.

Stefano Fassina of Bersani's leftwing Democratic party is predicting another election:

The scenario from the projections we have seen so far suggest there will be no stable government and we would need to return to the polls.

It was unrealistic to imagine a broad coalition between the centre-left and the centre-right led by Silvio Berlusconi, he told Rai.

Updated at 5.20pm GMT

4.28pm GMT

Projections from Rai, Sky, Mediaset and LA 7 are all now showing Berlusconi's centre-right coalition ahead in the Senate.

As Reuters writes, Italy's electoral laws guarantee a strong majority in the lower house to the party or coalition that wins the biggest share of the national vote, but the Senate, elected on a region-by-region basis, is more complicated, and the result will turn on four key battleground regions. Projections from LA 7 show Berlusconi winning in three of them: Lombardy, Sicily and Campania.

Berlusconi has said he would serve as finance minister, rather than prime minister, if his party ends up leading the government. The party secretary, Angelino Alfano, would be PM in such a scenario.

We're still waiting for the projections from the Chamber of Deputies, but if they contradict the exit polls in the same way this may mark an amazing comeback for Berlusconi. Either that or his centre-right coalition will dominate the Senate while the centre-left dominates the Chamber of Deputies – deadlock.

Unless, of course, all polls and projections so far turn out to be wrong …

Updated at 4.26pm GMT

4.07pm GMT

The new projections suggesting a Berlusconi majority in the Senate have sent shares sliding on the Milan stock market, reports Graeme Wearden.

Having been up 4% when investors expected a Bersani win, the FTSE MIB is now down by 0.5%. The FTSE 100 has also turned red (down 11 points in late trading).

Dizzying, and worrying. Steve Collins, global head of dealing at London & Capital Asset Management, says there could be a major sell-off if the election does result in deadlock.

Steve Collins (@TradeDesk_Steve)

Exit polls were wrong maybe ... could it be people were embarrassed to admit they voted for you know who >?>>

Enrico Letta, the deputy leader of Bersani's Democratic party, said, after hearing the first projections:

If things are this way, the next parliament will be ungovernable. A new electoral law will be passed straight away and we'll go back to the polls.

3.51pm GMT

Sky's forecast (as opposed to exit poll) for the Senate backs up Rai's and also contradicts its earlier exit poll, according to La Stampa, which puts the figures at:

Senate:

Centre-right coalition: 31.7%

Centre-left coalition: 29%

Five Star Movement: 25.1%

Centrist coalition: 8.5%

Rai has also updated its Senate forecast:

Senate:

Centre-right coalition: 31.6%

Centre-left coalition: 29.4%

Five Star Movement: 24.9%

Centrist coalition: 9.2%

Updated at 3.51pm GMT

3.45pm GMT

The first projections of the result based on the actual count are contradicting the exit polls – they show Silvio Berlusconi's centre-right alliance ahead of the centre-left in the Senate by 31% to 29.5%.

Earlier, two exit polls had shown Pier Lugi Bersani's centre-left coalition ahead in both the Senate and the Chamber of Deputies.

A party needs a majority in both in order to govern.

We are still awaiting projections from the Chamber of Deputies.

Lizzy Davies and John Hooper report from Rome:

The unexpected turnaround sent the interest rate on Italy’s debt up sharply as traders took fright at the prospect of a divided parliament with different majorities in the upper and lower houses.

One of the projections made the Five Star Movement (M5S) of Beppe Grillo Italy’s leading party. Because it is running alone and not in a coalition, however, it lagged behind the two big centre-left and centre-right alliances.

An exit poll for Rai, the state broadcaster, had put the centre-left bloc of the PD and its allies on 35-37% of the vote in the lower house of parliament and 36-38% in the Senate.

The centre-right bloc led by Berlusconi’s Freedom People party was in second position, with 29-31% and 30-32% in the Senate. The same poll put the M5S in third, and Monti’s centrist grouping significantly behind in fourth. The results were roughly echoed by a separate exit poll for Sky television.

Updated at 4.03pm GMT

3.39pm GMT

Anna Masera of La Stampa reports that Rai's forecast for the Senate (as opposed to its exit poll) shows Grillo's Five Star Movement as the largest party, and the rightwing coalition in the lead in the upper house. If so, Italy's exit polls have been proved unreliable once again. More details soon ...

Computer projections of the result in both houses are expected shortly, and could alter the picture.

Updated at 3.25pm GMT

3.06pm GMT

Lizzy Davies and John Hooper in Rome send a recap on where we are so far. The centre-left appears to be heading for victory, but it is unclear whether this "Italy. Common Good" alliance, led by Pier Luigi Bersani’s Democratic party, will end up with the outright majority in both houses of parliament it will need to govern the country.

Rai TV's polling shows

Chamber of Deputies:

Centre-left coalition (Bersani): 35-37%

Centre-right coalition (Berlusconi): 29-31%

Five Star Movement (Grillo): 19-21%

Centrist coalition (Monti): 8-10%

Senate:

Centre-left coalition: 36-38%.

Centre-right coalition: 30-32%

Five Star: 17-19%

Centrist coalition: 7-9%

Sky's polling shows

Chamber of Deputies:

Centre-left coalition (Bersani): 34.5%

Centre-right coalition (Berlusconi): 29%

Five Star Movement (Grillo): 19%

Centrist coalition (Monti): 9.5%

Senate:

Centre-left coalition (Bersani): 37%

Centre-right coalition (Berlusconi): 31%

Five Star Movement (Grillo): 16.5%

Centrist coalition (Monti): 9%

Lizzy and John write:

Observers cautioned against setting too much store by the initial indications, which have proved unreliable in the past.

However the numbers were enough to reinforce the pre-electoral prediction that Bersani’s party would win the most seats in the Chamber of Deputies.

The fate of the Senate is less clear. The result there will rest on key regions such as Lombardy, where the centre-right in alliance with the Northern League could win and thus deprive the centre-left of seats it would need for a majority.

Sky’s exit poll said the result there was tied.

Another crucial factor will be whether Monti’s centrist bloc manages to gain enough seats in the Senate to be of use to Bersani's PD as a potential governing ally.

Turnout, according to exit polls, was significantly down on the last election in 2008.

The parliamentary elections will mark the end of Monti’s technocratic government, brought in at the end of 2011.

The fractured nature of the political landscape and complexities of the electoral system have raised fears that recession-mired Italy, which has had a decade of near-economic stagnation and more than a year of punishing austerity, could end up with a deadlock in which no strong government is possible.

Updated at 3.23pm GMT

2.56pm GMT

Investors like the look of the exit polls, writes Graeme Wearden: shares in Milan jumped as soon as they were released, and the FTSE MIB (the main index) is now up by a hefty 3.8%.

Traders like the look of Bersani's lead over Berlusconi - even though crucial Senate seats are still in the balance.

Bank shares are leading the rally - gaining at least 6% each. Trading in Monte dei Paschi Siena, Italy's oldest bank, which has been hit by a major scandal, has just been paused because its shares jumped so strongly.

And shares in Mediaset, the media empire owned by Berlusconi, jumped by over 8%.

Italy's government bonds are also surging, as traders calculate that Bersani will form a stable administration. He's expected to stick, broadly, to the economic reforms and fiscal consolidation (austerity, basically) that Brussels demands.

The yield, or interest rate, on an Italian 10-year bond has dropped to 4.2%, from 4.45% last Friday night. That's a sizeable move in one day, and shows investors see the country as a safer bet (compared with the 7% levels hit in November 2011 when Berlusconi was forced from office).

If the exit polls are right – and attenzione: they have a chequered history in Italy – then it’s going to be a cliff-hanger, writes John Hooper in Rome. John notes:

It looks as if it will all come down to two factors: the direction of a handful of votes in Lombardy, the region around Milan (see map below), and whether the list put together by the outgoing prime minister, Mario Monti, can get over the threshold for entry to the Senate.

The key exit poll is the one that gives regional predictions for the upper house. The rules assign bonus seats in the Senate, region to region, to whichever party comes top, so you need to have all or most of the bigger regions in your pocket to win control.

And you can’t govern Italy without being in command of both houses, because they have equal powers.

Sky’s exit polls give Sicily and Campania to the centre-left. But Lombardy is too close to call.

According to Roberto D’Alimonte, professor of political science at the Luiss university, in Rome, if Bersani's leftwing Democratic party and its allies fail to take Lombardy, they could end up with only 155 Senate seats – three short of a majority.

The question then would be whether the seventh cavalry, in the form of Monti and his chums, can come to the rescue. They are the only realistic coalition partners for the centre-left.

But they need more than 8% of the votes in any one region to get a seat in the Senate, and the exit polls are giving them between 7% and 9%. It looks as if they will get some seats but not as many as were predicted at the start of the campaign.

I'm not overly impressed by the bad language in the previous posts. Berlusconi also swears alot as does Grillo, they aren't particularly intelligent either. Italy needs more than a few bad words to get it out of its problems.

Culture and society are the main issues that need addressing.

Many of my friends went to vote yesterday, they hold no false preconceptions that the situation will improve or that any of the candidates are strong enough to lead a failing country. I quote one good friend "the best of a bad lot".

Whoever wins will is unlikely to survive for long, the new government will collapse and they will be back to vote again in a few months time, probably without the snow.

This comment has been chosen by Guardian staff because it contributes to the debate

@hrwaldram - Hello there, the atmosphere is pretty much the same of the last elections. I live just outside Milan and though it snowed a lot (we are used to it here) we had plus 7% people voting for the regional polls while for the general election we had a -4%. In Lombardy we are voting for regional and general elections.What stopped some people from going to vote is not the snow for sure. But the fact they don't belive in any of the candidates for the leadership of the Country.

And here's Berlusconi being assailed by his bugbear "communist judges" in Lego by Flickr photographer JETfri.

Updated at 2.45pm GMT

2.24pm GMT

The Sky poll also showed the centre-left and the centre-right neck and neck in the Senate race for Lombardy. The centre-left was ahead in Sicily and Campania, and the centre-right in Veneto.

After the first day of voting on Sunday, about 54% of voters had cast their ballots, a sharp fall on the level of 62.5% seen at the same stage in the last election in 2008.

Bad weather, including heavy snow in some areas, is thought to have hampered the turnout in Italy's first post-war election to be held in winter. This could favour the centre-left, whose voters tend to be more committed than those on the right, which has strong support among older people.

Shares on the Italian stock market have jumped today, reports Graeme Wearden, because of optimism that the election will deliver a clear victory for Pier Luigi Bersani's party, perhaps in a coalition with Mario Monti. Graeme reports:

The Italian FTSE MIB is up 339 points, or more than 2%. The euro has also rallied today - up 1.5p against the pound (which is suffering from Britain's triple-A downgrade).

Traders had nervously watched Silvio Berlusconi's revival, fearing that the election would result in deadlock. The markets, like the eurocrats in Brussels, would like to see a strong government in Italy that is committed to economic reforms, austerity, and Italy's place in the euro.

Kit Juckes, global macro strategist at Societe Generale, explains: "The market is hoping that Berlusconi didn't do well and a low turnout keeps Five Star at bay, handing victory to Monti/Bersani, about the best outcome that we can get."

Updated at 2.37pm GMT

1.34pm GMT

The pollster Antonio Noto, director of IPR marketing, explains what the high level of abstention today and yesterday probably means:

We know that centre-right voters make up a disproportionate share of the potential abstainers. So the relatively high level of abstention we're seeing means that fewer centre-right voters are going to the polls and that favours both the centre-left and Grillo.

Updated at 2.37pm GMT

1.33pm GMT

In this interactive graphic, my colleagues John Hooper and Garry Blight look at five possible outcomes from the elections today – and what they mean for Italy, the euro and bunga bunga parties.

1.27pm GMT

Robert O’Daly, Italy analyst at the Economist Intelligence Unit, notes:

The election uncertainty coincides with heavy Italian government debt issuance this week of around €20bn (£17.6bn) in securities ranging from six-month Treasury bills to 10-year bonds.

Under a scenario where the combined parliamentary representation of Mr Bersani's centre-left and Mr Monti's centrists is insufficient to form a majority, a period of minority government followed by further elections would be likely.

Such an outcome would place strong additional upward pressure on government borrowing costs. If this were to continue for a prolonged period, it could be destabilising for other distressed peripheral euro area countries.

Italy could conceivably be forced to seek external financial assistance from its euro-area partners to calm the bond markets.

1.19pm GMT

Hello, and welcome to the Guardian’s live coverage of the Italian election results.

The first exit polls are expected from 2pm GMT (3pm Rome time) – though they have been inaccurate before. Early projections for the Senate are due from 3pm GMT and for the Chamber of Deputies from 5pm GMT.

The election campaign had been expected to be dominated by the former prime minister Silvio Berlusconi’s comeback, but in the event the big story so far has been the success of the anti-establishment Five Star Movement, led by comedian Beppe Grillo.

Grillo has vowed not to go into government with any of the main parties, leading to fears of political stalemate and economic turmoil if none of the others get a good enough showing to form a viable coalition.

He is also committed to holding a referendum on leaving the euro and implementing a temporary freeze on interest payments on government bonds, which could lead to default. The 64-year-old comic will not enter parliament: he has a 1980 driving conviction for manslaughter after a crash in which passengers were killed, and thus falls foul of his own rule banning MPs with criminal records.

The EU political establishment and financial markets are said to be hoping for a left/centre-left coalition to emerge.

The main parties are:

•People of Freedom, formed by Berlusconi in 2007, which leads a rightwing bloc.

•Italy. Common Good, led by Pier Luigi Bersani, which leads a centre-left grouping.

•Civic Choice, led by the centrist technocrat Mario Monti, the current PM, which leads a centrist bloc.